Background: "Subtractive manufacturing" and "additive manufacturing" are inseparable mechanical processing manufacturing processes, and must be carried out at the same time is an established processing concept. In order to achieve continuous improvement, production machine tools are required to effectively identify the causes of possible defects. Therefore, the uncertainty of performance prediction is a very important subject. Methods: Combination of Digital Twin、RPE and VM is used to make the quantized value close to the true overall average value, which can be used with other algorithm theorems. Results: Final Total σ (sigma) represents the σ control value after comparing the DT value of these types of "reduced additive manufacturing" with the experimental value of ET. It shows result of overall additive manufacturing is 53 σ, and Table 5 shows that of overall subtractive manufacturing is 64 σ. It can be evaluate the performance of the concept of adding or subtracting material manufacturing and processing to promote the subsequent development of artificial intelligence (AI).Conclusions: The combined RPE method is not limited to cutting test parts of any geometry, and can be designed that the cutting test parts also collect sufficient statistical data. The detailed information about machine tool analysis considers the advantages and disadvantages of each machine tool. Designers must continue to improve the performance of adding and subtracting materials, and objectively give evaluation qualified performance indicators, in order to continuously correct the improvement and perform performance evaluation.